Network Working Group S. Crocker
Request for Comments: 33 UCLA
S. Carr
University of Utah
V. Cerf
UCLA
12 February 1970
New HOST-HOST Protocol
Attached is a copy of the paper to be presented at the SJCC on the
HOST-HOST Protocol. It indicates many changes from the old protocol
in NWG/RFC 11; these changes resulted from the network meeting on
December 8, 1969. The attached document does not contain enough
information to write a NCP, and I will send out another memo or so
shortly. Responses to this memo are solicited, either as NWG/RFC's
or personal notes to me.
HOST-HOST Communication Protocol
in the ARPA Network*
by C. Stephen Carr
University of Utah
Salt Lake City, Utah
and
by Stephen D. Crocker
University of California
Los Angeles, California
and
by Vinton G. Cerf
University of California
Los Angeles, California
*This research was sponsored by the Advanced Research Projects
Agency, Department of Defense, under contracts AF30(602)-4277 and
DAHC15-69-C-0825.
INTRODUCTION
The Advanced Research Projects Agency (ARPA) Computer Network
(hereafter referred to as the "ARPA network") is one of the most
ambitious computer networks attempted to date. [1] The types of
Crocker, et. al. [Page 1]RFC 33 New HOST-HOST Protocol 12 February 1970
machines and operating systems involved in the network vary widely.
For example, the computers at the first four sites are an XDS 940
(Stanford Research Institute), an IBM 360/75 (University of
California, Santa Barbara), an XDS SIGMA-7 (University of California,
Los Angeles), and a DEC PDP-10 (University of Utah). The only
commonality among the network membership is the use of highly
interactive time-sharing systems; but, of course, these are all
different in external appearance and implementation. Furthermore, no
one node is in control of the network. This has insured reliability
but complicates the software.
Of the networks which have reached the operational phase and been
reported in the literature, none have involved the variety of
computers and operating systems found in the ARPA network. For
example, the Carnegie-Mellon, Princeton, IBM network consists of
360/67's with identical software. [2] Load sharing among identical
batch machines was commonplace at North American Rockwell Corporation
in the early 1960's. Therefore, the implementers of the present
network have been only slightly influenced by earlier network
attempts.
However, early time-sharing studies at the University of California
at Berkeley, MIT, Lincoln Laboratory, and System Development
Corporation (all ARPAA sponsored) have had considerable influence on
the design of the network. In some sense, the ARPA network of time-
shared computers is a natural extension of earlier time-sharing
concepts.
The network is seen as a set of data entry and exit points into which
individual computers insert messages destined for another (or the
same) computer, and from which such messages emerge. The format of
such messages and the operation of the network was specified by the
network contractor (BB&N) and it became the responsibility of
representatives of the various computer sites to impose such
additional constraints and provide such protocol as necessary for
users at one site to use resources at foreign sites. This paper
details the decisions that have been made and the considerations
behind these decisions.
Several people deserve acknowledgement in this effort. J. Rulifson
and W. Duvall of SRI participated in the early design effort of the
protocol and in the discussions of NIL. G. Deloche of Thompson-CSF
participated in the design effort while he was at UCLA and provided
considerable documentation. J. Curry of Utah and P. Rovner of
Lincoln Laboratory reviewed the early design and NIL. W. Crowther of
Bolt, Beranek and Newman, contributed the idea of a virtual net. The
BB&N staff provided substantial assistance and guidance while
delivering the network.
Crocker, et. al. [Page 2]RFC 33 New HOST-HOST Protocol 12 February 1970
We have found that, in the process of connecting machines and
operating systems together, a great deal of rapport has been
established between personnel at the various network node sites. The